Inverters convert DC power into AC power. A common inverter application is to convert power from a variable DC source into constant voltage AC power to supply an electrical grid. Many DC power sources, such as a solar photovoltaic panel or a windmill, for example, have a variable power output. In many inverter designs portions of the inverter are located in separate power domains and are physically isolated from each other without connected return paths. This situation represents a challenge in terms of inverter control for proper functioning. In some implementations, separate controllers are provided, including one controller for each power domain.